BEECH ASSOCIATION 243 
a) Subterranean-ground stratum.—Earthworms continue; an occa- 
sional groundhog has been seen, though they are probably much less 
common here than in the preceding stages. The stratum appears less 
closely inhabited than the preceding. Under leaves are found scattered 
snails, centipedes, etc. The yellow-margined millipede (Fontaria cor- 
rugale) is most common. There is an occasional Centhophilus. We 
have found no other Orthoptera in beech woods proper, though 
Hancock records several (40, p. 422). Animals are more abundant 
under logs than under leaves. Here we find the large slug (Philomycus 
carolinensis) and several species of snails which, though characteristic, 
238 239 240 
Fires. 234-240.—Some beech woods snails: Ground stratum; 234, Pyramidula 
pers pectiva; 235, Polygyra inflecta; 236, Polygyra palliata; 237, Polygyra fraudulenta; 
238, Polygyra oppressa; 239, Pyramidula solitaria, adult; 240, Polygyra albolabris. 
are not abundant. These snails are Polygyra inflecta (Fig. 235), 
oppressa (Fig. 238), fraudulenta (Fig. 237), palliata (Fig. 236), albolabris 
(Fig. 240), Pyramidula solitaria (Fig. 239), alternata, and perspectiva 
(Fig. 234), and Zonitoides arboreus. ‘These species of Polygyra are 
distinguishable by the presence of characteristic “teeth” in the 
entrance of the shells. The large spider (Dolomedes tenebrosus) and 
millipede (Spirobolus marginatus) occur. Crane-fly larvae, ground 
beetles (Plerostichus adoxus), a centipede (Geophilus rubens), the wood- 
frog (Rana sylvatica) (Fig. 241) (139), and the red-backed salamander 
(Plethodon cinereus) (152) (Fig. 242) are common and characteristic. 
